By age 42, I had lived in seven apartments/flats in Boston, London and on Manhattan’s Upper East and Upper West sides. Even when I owned a co-op on West 97th Street, I viewed the dwelling as a stepping stone to the next great adventure in my life.

That presumption panned out seven years later when in 2005, after finding love and motherhood, I sold the co-op and bought an old farmhouse on an acre of land in suburbia.

There’s a theory behind the phrase “seven-year itch.” It is said that human beings go through an evolutionary shift every seven years. Something draws us into the next stage at 7, 14, 21, etc. I look back on my own life and know this to be true.

Moving from the city to the hinterlands in my early 40s was among my biggest life leaps. In the past four years, I’ve renovated a house to cater to my pleasures — especially my roomy light-filled kitchen and my Tuscan-tile bathroom. I’ve nested so hard I feel as though I could lay eggs.

This stage of my life has been filled with unexpected gleanings, such as learning to garden, cut wood and bake bread. I love the 3-mile walks around Rockland Lake and the French pastry shop in the village. I know which trees flower first in spring and which direction mud runs down our mountain after ice melts.

There’s a squirrel that comes right up to my window and presses his nose against the glass. I — and the cat on my desk — do the same on the other side.

In the first couple of years we were here, I would say to my husband that “the next time we move, we’ll have to take the house with us.” I couldn’t imagine living in any other home. He’d say the 150-year-old house that sits on a thick stone foundation wouldn’t make it a mile on a flatbed on the highway. Oh well.

I love the house as much as ever, but tick-tock, tick-tock — 49 is two years away. I feel a faint but unmistakable itch.

This time around, though, a move might not be in the cards.

The cratered real estate market, job uncertainty and economic jitters have most homeowners, including me, in a fetal position. I won’t even allow myself to do the mental math that would show the losses I’d incur if I were to sell now.

I remember when I put my Manhattan co-op up for sale and it sold within a week. These days, “For Sale” signs linger longer on lawns than garden gnomes.

My husband and I still play the irresistible parlor game: Where will we be and what will we be doing when we turn 50?

I lobby for running a small inn in Massachusetts’ Berkshires or buying a wee farm upstate where we’d have richer soil and room for goats and chickens. He likes the overseas dream: “What about living in Lisbon? It’s such a temperate climate.”

Some version of these fantasies would be in play now if these were exuberant times — but they’re not.

I count my blessings that I have plenty of equity and can still afford to live in my modest house. But what freaks me out is that for the first time in my life, I feel tethered to a place. Like everyone else, I can hardly believe how this economic meltdown has hurt property values and paralyzed credit markets.

My generation is going to need to change its presumptions about mobility. Maybe my husband and I won’t live in our house for 35 years, but we’re likely to be here longer than expected.